• Title/Summary/Keyword: Dimethyl sulfur (DMS)

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Attractive Sulfur...π Interaction between Fluorinated Dimethyl Sulfur (FDMS) and Benzene

  • Yan, Shihai;Lee, Sang-Joo;Kang, Sun-Woo;Choi, Kwang-Hyun;Rhee, Soon-Ki;Lee, Jin-Yong
    • Bulletin of the Korean Chemical Society
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    • v.28 no.6
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    • pp.959-964
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    • 2007
  • The benzene complexes with dimethyl sulfur (DMS) and fluorinated DMS (FDMS) have been investigated using ab initio calculations. The natural bond orbital (NBO) charge population on S atom varies remarkably for different conformations of DMS and FDMS, which determines the possible binding modes for their benzene complexes. The electronegative substituent at the methyl group of DMS causes a significant change in the molecular electrostatic potential around the sulfur atom and changes the interaction mode with aromatic ring. It was found that the sulfur…π interaction mode does not occur in the DMS-benzene complex, while it does in the FDMS-benzene complex. Both B3LYP and MP2 methods provide reliable structures, while the interaction energy obtained by B3LYP is unreliable.

Overall Conversion Efficiency for Dimethylsulfide to Sulfur Dioxide in the Marine Boundary Layer-An Overview

  • Shon, Zang-Ho
    • Journal of Korean Society for Atmospheric Environment
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    • v.18 no.E2
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    • pp.107-120
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    • 2002
  • Dimethyl sulfide (DMS) is the major sulfur gas released from the ocean. The atmospheric DMS released from the ocean is oxidized mainly by hydroxyl (OH) radical during the day and nitrate (NO$_3$) radical at night to form sulfur dioxide (SO$_2$) as well as other stable products. The oxidation mechanism of DMS via OH has been known to proceed by two channels; abstraction and addition channels. The major intermediate product of the addition channel has been known to be dimethylsulfoxide (DMSO) based on laboratory chamber studies and field experiments. However, a branching ratio for DMSO formation is still uncertain. The reaction of DMSO with OH ultimately produces SO$_2$and dimethylsulfone. The major product of the abstraction channel has known to be SO$_2$from laboratory chamber studies. But overall conversion efficiency for DMS to SO$_2$from DMS oxidation is still inconsistent in the literature. Based on laboratory and field studies, the conversion efficiency from the abstraction channel is likely to be greater than 0.5, while that from the addition channel is likely to be greater than 0.6. Overall conversion efficiency from DMS to SO$_2$might be greater than 0.5 based on the above two values in the remote marine boundary layer (MBL). This high efficiency in the remote MBL is supported by strong coupling between DMS and SO$_2$measurements with high temporal resolution.

Control of Low-Level Dimethyl Sulfide and Dimethyl Disulfide by Applying Element-Doped Photocatalysts (원소-도핑 광촉매를 활용한 저농도 황화 이메틸 및 이황화 이메틸의 제어)

  • Shin, Myeong-Hee;Jo, Wan-Kuen
    • Journal of Environmental Science International
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    • v.18 no.11
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    • pp.1215-1224
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    • 2009
  • This study evaluated the applicability of visible-light-driven N- and S-doped titanium dioxide($TiO_2$) for the control of low-level dimethyl sulfide(DMS) and dimethyl disulfide(DMDS). In addition, a photocatalytic unit(PU)-adsorption hybrid was evaluated in order to examine the removal of DMS and DMDS which exited the PU and a gaseous photocatalytic byproduct($SO_2$) which was generated during the photocatalytic processes. Fourier-Tranform-Infrared(FTIR) spectrum exhibited different surface characteristics among the three-types of catalysts. For the N- and S-doped $TiO_2$ powders, a shift of the absorbance spectrum towards the visible-light region was observed. The absorption edge for both the N- and S-doped $TiO_2$ was shifted to $\lambda$ 720 nm. The N-doped $TiO_2$ was superior to the S-doped $TiO_2$ in regards to DMS degradation. Under low input concentration(IC) conditions(0.039 and 0.027 ppm for DMS and DMDS, respectively), the N-doped $TiO_2$ revealed a high DMS removal efficiency(above 95%), but a gradual decreasing removal efficiency under high IC conditions(7.8 and 5.4 ppm for DMS and DMDS, respectively). Although the hybrid system exhibited a superior characteristic to PU alone regarding the removal efficiencies of both DMS and DMDS, this capability decreased during the course of a photocatalytic process under the high IC conditions. The present study identified the generation of sulfate ion on the catalyst surface and sulfur dioxide(maximum concentrations of 0.0019 and 0.0074 ppm for the photocatalytic processes of DMS and DMDS, respectively) in effluent gas of PU. However, this generation of $TiO_2$ would be an insignificant addition to indoor air quality levels.

Desulfurization of Model Oil via Adsorption by Copper(II) Modified Bentonite

  • Yi, Dezhi;Huang, Huan;Li, Shi
    • Bulletin of the Korean Chemical Society
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    • v.34 no.3
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    • pp.777-782
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    • 2013
  • In order to further reduce the sulfur content in liquid hydrocarbon fuels, a desulfurization process by adsorption for removing dimethyl sulfide (DMS) and propylmercaptan (PM) was investigated. Bentonite adsorbents modified by $CuCl_2$ for the desulfurization of model oil was investigated. The results indicated that the modified bentonite adsorbents were effective for adsorption of DMS and PM. The bentonite adsorbents were characterized by X-ray diffraction (XRD) and thermal analysis (TGA). The acidity was measured by FT-IR spectroscopy. Several factors that influence the desulfurization capability, including loading and calcination temperature, were studied. The maximum sulfur adsorption capacity was obtained at a Cu(II) loading of 15 wt %, and the optimum calcination temperature was $150^{\circ}C$. Spectral shifts of the ${\nu}$(C-S) and ${\nu}$(Cu-S) vibrations of the complex compound obtained by the reaction of $CuCl_2$ and DMS were measured with the Raman spectrum. On the basis of complex adsorption reaction and hybrid orbital theory, the adsorption on modified bentonite occurred via multilayer intermolecular forces and S-M (${\sigma}$) bonds.

Control of Low-level Malodorous Reduced Sulfur Compound with Visible-light Irradiation

  • Sin, Myeong-Hui;Kim, Jong-Tae;Jang, Jong-Dae;Kim, Mo-Geun;Gwon, Gi-Dong;Lee, Hyeon-Cheol;Jo, Wan-Geun
    • Proceedings of the Korean Environmental Sciences Society Conference
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    • 2008.11a
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    • pp.103-106
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    • 2008
  • 악취물질 중 특히 황계열 물질인 Dimethyl sulfide(DMS)을 가시광선 조사아래 실내환경조건에서 광촉매 제거효율을 평가하였다. 농도에 의한 영향에서 1000, 20000$\mu$g/m$^3$에서 램프를 켜자마자 활성이 저하되는 것을 발견하였다. 이는 촉매 산화반응에 의한 부산물의 흡착 때문이다. 습도에 의한 영향평가에서 습도가 낮을 수로 제거율도 떨어졌다. 이는 유기물 산화를 일으키는 라디칼이 물분자에 의해 생성되기 때문에 낮은 습도에서 OH 의 공급원인 물분자의 결핍이 생겨 Dimethyl sulfide(DMS)제거효율을 떨어뜨렸다.

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Removal of Malordorous Sulfur Compounds by Thiobacilius neapolitanus R-10 (Thiobacillus neapolitanus R-10에 의한 유황계 악취물질의 제거)

  • 원용돈;박상보
    • Journal of Environmental Science International
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    • v.4 no.2
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    • pp.215-222
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    • 1995
  • Thiokncillus neapolitanus R-10 isolated from sludge of night soil, showed an oxidizing activity on several malodorous sulfur compounds. The microbe successfully utilized hydrogen sulfide(H2S), methy mercaptan(MM), dimethyl sulfide(DMS) and dimethyldisulfide(DMDS) during the batch culture reaction, of which H2S was rather rapidly oxidized. To examine the ability for removal of malodorous sulfur compounds, various concentrations of sulfide substrates were supplemented separately to basal medium and their responses were investigated. As the concentration of sulfide was increased, growth was accelerated within three days of cultivation. 2.5mM was the most favorable substrate concentration of sulfide added for all cases tested. However, when the concentration of sulfur compounds were raised over 4M, they behaved as a growth inhibitor.

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Effect of Ozone Application on Sulfur Compounds and Ammonia Exhausted from Aerobic Fertilization System of Livestock Manure (가축분뇨 호기적 퇴.액비화시 발생하는 기체 중의 황 화합물과 암모니아에 대한 오존처리 효과)

  • Jeong, Kwang Hwa;Whang, Ok Hwa;Khan, Modabber Ahmed;Lee, Dong Hyun;Choi, Dong Yoon;Yu, Yong Hee
    • Journal of the Korea Organic Resources Recycling Association
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    • v.20 no.4
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    • pp.118-126
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    • 2012
  • In this study, two types of ozone generating experimental instrument were installed in commercial livestock manure fertilization facility, which can treat hundred tons of pig manure in a day. Gas samples to be treated were collected from the upper part of the liquid fertilization system and composting system of the commercial livestock manure fertilization facility. The gas sample was flowed to oxidation reactor through pipe line by suction blower, therefore, contacted with ozone. Ammonia and sulfur compounds of gas samples collected from the inlet and outlet point of the experimental instrument were analyzed. The oxidation effect by the contact with ozone was higher in sulfur compounds than ammonia. Ammonia content was reduced about 10% by ozone contact. Sulfur compounds, on the other hand, reduced significantly while treated with ozone. In case of gas sample collected from liquid fertilization system, the concentrations of hydrogen sulfide ($H_2S$), methyl mercaptan (MM), dimethyl sulfide (DMS), and dimethyl disulfide (DMDS) of inlet gas were 50.091, 4.9089, 27.8109 and 0.4683 ppvs, respectively. After oxidized by ozone, the concentrations of sulfur compounds were 1.2317, 0.3839, 14.7279 and 0.3145 ppvs, respectively. Another sample collected from aerobic composting system was oxidized in the same conditions. The concentrations of $H_2S$, MM, DMS and DMDS of the sample collected from inlet point of the reactor were 40.6682, 1.3675, 24.2458 and 0.8289 ppvs, respectively. After oxidized, the concentrations of $H_2S$, MM, DMS, and DMDS were reduced to 3.013, ND, 8.8998 and 0.3651 ppvs, respectively. By application of another type of ozone, the concentrations of $H_2S$, MM, DMS and DMDS of inlet gas were reduced from 43.397, 1.4559, 3.6021 and 0.4061 to ND, ND, ND, and 0.21ppvs, respectively.

Evaluation of Catalyst Deactivation and Regeneration Associated with Photocatalysis of Malodorous Sulfurized-Organic Compounds (악취유발 황화유기화합물질의 광촉매분해에 따른 촉매 비활성화와 재생 평가)

  • Jo, Wan-Kuen;Shin, Myeong-Hee
    • Journal of Korean Society of Environmental Engineers
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    • v.31 no.11
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    • pp.965-974
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    • 2009
  • This study evaluated the degradation efficiency of malodorous sulfurized-organic compounds by utilizing N- and Sdoped titanium dioxide under visible-light irradiation, and examined the catalyst deactivation and regeneration. Catalyst surface was characterized by employing Fourier-Transform-Infrared-Red (FTIR) spectra. The visible-light-driven photocatalysis techniques were able to efficiently degrade low-level dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) with degradation efficiencies exceeding 97%, whereas they were not effective regarding the removal of high-level DMS and DMDS, with degradation efficiencies of 84 and 23% within 5 hrs of photocatalytic processes. As compared with DMS, DMDS which containes one more sulfur element revealed quick catalyst deactivation. Catalyst deactivation was confirmed by the equality between input and output concentrations of DMD or DMDS, the obsevation of no $CO_2$ generation during a photocatalytic process, and the FTIR spectrum peaks related with sulfur ion compounds, which are major byproducts formed on catalyst surfaces. The mineralization efficiency of DMS at 8 ppm, which was a peak value during a photocatalytic process, was calculated as 144%, exceeding 100%. The catalyst regenerated by high-temperature calcination exhibited higher catalyst recovery efficiency (53 and 58% for DMDS and DMS, respectively) as compared with dry-air and humid-air regeneration processes. However, even the calcined method was unable to totally regenerate deactivated catalysts.

The Analysis of Sulfur Compounds of Odorous Material in Kunsan Industrial Complex

  • Kim, Seong-Cheon;Kim, Ki-Hyun;Choi, Yeo-Jin
    • Proceedings of the Korean Environmental Health Society Conference
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    • 2005.06a
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    • pp.399-405
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    • 2005
  • In this study, we investigated the gas chromatography (GC) and pulsed flame photometric detection (PFPD) system for the analysis of four major reduced S compounds including hydrogen sulfide ($H_2S)$; methyl mercaptan ($CH_3SH$); dimethyl sulfide (DMS); and dimethyl disulfide(DMDS) contained in environmental samples. To analyze these compounds in high concentration range (above ppb level), we developed a high mode analytical setting with the loop-injection system. By contrast, we also established a low mode setting for the analysis of low concentration samples (ppt-level samples from ambient air) by the combination with thermal desorption unit(TDU). Comparative analysis of both settings revealed that relative detection properties of four S compounds are systematic enough. The results of high mode analysis indicated that the patterns were systematic among compounds: H2S exhibited the lowest sensitivity, while DMBS showed the strongest one. The results were also compared in terms of sensitivity reductions for all compounds by dividing slope ratios between low and high mode system. Although low mode system exhibited significant reductions on the order of a few tens times, their detection characteristics were highly consistent as it was shown in the high mode setting. To learn more about absolute and relative relations between two different modes of S analysis, future studies may have to be directed to cover more complicated nature of GC/PFPD performance. Hydrogen sulfide($H_2S$) was over in summer about low level of olfactory sense 410 ppt, Methyl mercaptan(C$H_3SH$) was over in apring and summer about low level of olfactory sense 70, Dimethyl sulfide(DMS) was not over in four season about low level of olfactory sense 2,200 ppt. Carbon disulfide($CS_2$) was not over in four deason about Tow level of olfactory sense 210,000, Dimethyl disulfide(DMDS) was not over in summer about low level of olfactory sense2,000.

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The Analysis of LFG Composition with Respect to Malodorous Sulfur Compounds (환원황 화합물을 중심으로 한 매립가스의 조성에 대한 연구)

  • 김기현;오상인;최여진;전의찬;사재환;선우영
    • Journal of Korean Society for Atmospheric Environment
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    • v.20 no.1
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    • pp.77-85
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    • 2004
  • In this study, the concentrations of reduced S compounds (including hydrogen sulfide (H$_2$S); methyl mercaptan ($CH_3$SH); dimethyl sulfide (($CH_3$)$_2$S); carbon disulfide (CS$_2$); and dimethyl disulfide (($CH_3$)$_2$S$_2$) were determined from landfill gas (LFG) in three municipal landfill sites in the two cities of Gwang Ju (GJ) and Jeju (JJ), Korea. The S gas concentrations measured in these landfill sites were found to be dominated by H$_2$S with its mean concentration of 850 ppm from 10 LFG samples. Both absolute and relative dominance of H$_2$S was seen to be significant in most LFG samples, except those collected from very old and inactive landfills. Unlike the pattern of H$_2$S, other S gases were typically observed at much reduced concentration levels (a few ppm or less) as follows: DMS (3.5); $CH_3$SH (1.3); CS$_2$(1.2); and DMDS (0.02 ppm). If compared equally in mass concentration unit (mg m$^{-3}$ ), H$_2$S generally explained far above 90% of all S gas masses determined concurrently. Moreover, as its mass concentration commonly exceeds those of the major aromatic VOC components in LFG (like benzene and toluene), it appeared to be one of the most dominant gaseous components emitted as LFG in a quantitative sense.